Hand-held power tools, such as grinders, sanders, saws, and the like include a motor driven arbor shaft to which is mounted an appropriate tool head, such as a grinding wheel, sanding disk, or circular saw blade. The arbor is typically threaded, allowing a tool hub to be affixed thereon, such as by a mounting nut assembly. The hub may be an integral part of the rotary tool, but often a hub is provided as an intermediate coupling unit between the arbor and the tool element, which is removably mounted to the hub. This latter form of tool head construction is often preferred, as it allows the work-engaging tool element, such as a grinding wheel, to be removed from the hub when worn without disengaging the hub itself from the arbor shaft. Further, such a construction allows the replacement and interchange of the working tool elements without replacement of the hub. This is of significant value, since during the course of operation a variety of tool elements often are required. This provides for more economical tool element exchange and further lessens the down time of the tool for such exchange.
Various constructions have been proposed for mounting disk-shaped tools on a hub in a removable manner. U.S. Pat. No. 6,116,996 to Yanase, for example, utilizes a flange system in conjunction with a gravity-driven stopper to assist maintaining the tool disk in position on a hub-like member. U.S. Pat. No. 6,786,811 to Krondorfer, et al mounts a tool element through a system utilizing circumferential and axial locking elements. Often sanding disks and the like are removably mounted using hook-and-loop fastener systems. While such systems are satisfactory for low rpm operation, they may not provide sufficient holding power for high rpm applications.
Notwithstanding the efforts of others, it remains a goal in the tool art to provide a mounting system for rotary tools that allows a rotary tool to be easily and quickly mounted upon or removed from a hub, but securely retains the rotating tool upon the hub to prevent inadvertent disengagement therefrom over a wide range of operating speeds.
It is accordingly an object of the present invention to provide such a tool mount which is of economical construction, and allows a rotary tool to be quickly and efficiently mounted upon and removed from a tool hub typically mounted to a tool arbor.
It is a further purpose of the present invention to provide such a mounting system that further provides secure retention of the tool element in a fixed position on the hub to prevent inadvertent disengagement therebetween.